The DOM element where to render the object.

<div class="definition">
    DOM Element, default = null
</div>

Usually it is a DIV, but can be any block element.
If you change <span class="method">.box</span> property you will need to call <a class="method" href="common.render">.render()</a> method
to render widget inside the new DOM element. If you specify a selector, there is no need to define <a href="common.box">.box</a> because
it will be automatically set.

<textarea class="javascript">
let layout = new w2layout({
    name    : 'layout',
    panels  : [
        { type: 'top', size: 40 },
        { type: 'preview', size: 200 }
    ]
});
</textarea>

The layout is created in memory. You can render it in one of the following ways:

<textarea class="javascript">
$('#layout').w2render('layout'); // preferred way
</textarea>

or

<textarea class="javascript">
w2ui.layout.render($('#layout')[0]);
</textarea>

or

<textarea class="javascript">
w2ui.layout.box = $('#layout')[0];
w2ui.layout.render();
</textarea>